1. Field of the Invention
The present invention relates to video systems for multiplexing and encoding multiple video signals, and in particular, to video systems for encoding time-multiplexed video signals with selected display parameters which cause the associated video display to be a pattern of multiple video windows having selected window positions, sizes and visibilities.
2. Description of the Related Art
As video signal processing systems have increased and decreased in their sophistication and cost, respectively, their features and applications have increased accordingly. One feature in particular which has become increasingly popular is that of displaying multiple video "windows," wherein multiple video images are displayed either adjacent to one another or overlapping one another. Such a "windowed" display is formed by overlaying, or "keying," one or more video images over one another or over a shared background. The resulting composite video image can then be viewed or recorded, e.g. on a tape recorder, for later viewing. However, the individual video window images no longer include all of their original video information; i.e. only a portion of the original video information is retained since each video window image has been either compressed to fit within its respective window or "cropped" to display only a portion of the original image.
A partial solution to this is to time-multiplex, or interleave, the various video signals representing the video images sought to be viewed or recorded, with each video frame displayed on its own monitor with full resolution but at a reduced frame update rate. The foregoing techniques allow each video image to be viewed or recorded for later viewing, albeit with reduced resolution or update rates. However, no video window information, such as the selected position or size of each video window, is available. Therefore, any video windowing being viewed, which may have originally been done with the video images, cannot be reconstructed.
Accordingly, a limitation of the prior art has been the inability to combine multiple video images in a selectively windowed display, with selected window locations, sizes, update rates and viewing priorities suitable for transmission, or recording for later viewing, with reconstruction of the original, selected video windows.